Both PBC and SSc are associated with higher levels of certain proteins that promote fibrosis and are involved in the function of immune cells called T-helper (Th)-17 cells and regulatory T (Treg) cells, such as TGF-β (transforming growth factor) and IL-6 (interleukin 6) [30,48]. This evidence concerns the gene TGFB1 and primary biliary cholangitis.